1) you're not losing that much efficiency. Many of the Meanwells I've seen could be rated as "gold" by ATX standards, even the lower ones are commonly 88%.
 
 2) Haven't found a stepdown YET that's specified to run LONG TERM at the power draw of an S5 per hash board, a couple talk about "higher possible with a bigger heat sink" but no actual spec for that.

 3) The PSUs I already have will probably be getting transitioned to running an S7 or three....



 Side effect of their "keep it cheap" string design, doesn't seem to be deliberate.
 The old "pencil mod" was about changing an on-board regulator that doesn't exist on their current designs - and was STILL far inferior to Spondoolies methodology.




 Wish I could find a place with affordable rent and enough power/cooling in Chelan or Douglass counties.
 Then again, if I had $50k+ to put into this I wouldn't have to worry about the rent as much.

 8-O

 NOBODY in the USA is paying less than 2 cents / KWH. Best rate in the USA is a little under 3.

 And no, there ARE big farms that are not "next to big power plants", though I suspect a majority are in areas served by major hydro projects.

 On the other hand, at 3 cents / KWH I am pretty sure the S5 even in stock form at stock voltage will still be profitable after halfing. Barely. For a few months.


 More like you make appx. 5% of your investment as profit (edit - this seems to be slipping a bit, more like 4.5% right now) by the time the entire contract pays off after about 3-4 months, based on what I'm seeing out of my v3 contract.
 I suspect the "how long to complete" time will be going up as difficulty increases, how much is kinda up in the air right now.

 GIMPS?
 Or something else?

 18awg should easily handle 180ish watts - that's only 5 amps per wire.
 Come to think about it, THAT might be why they state "have to use all 3 connectors" - wire limits on the PS they tested the S7 on.




 You're joking, right?
 Probability ZERO if you're not joking.

 Hashnest is only JUST IN THE LAST WEEK OR SO prepping redemption of the S3.
 I'd predict S7 won't be redemption material for close to 2 YEARS.




 Better get your hearing checked, you seem to be starting to go deaf.

 9-)



 Not if your electric is cheap enough, though it's a near thing.
 On the other hand, these units SHOULD BE STILL PROFITABLE AFTER THE HALFING for a while - even if we don't get a pre-halfing price runup like Litecoin got the last couple months.

 You are assuming they have the contract priced for a miner that probably didn't EXIST yet when they came out with the v3 contract.
 I suspect in a few months they'll come out with a "V4" contract that references an "ideal S7" for it's stated cost of mining limit.

 1 TH is 1 TH - and if the S7 is making it so BitMain pays less electric for that 1TH, it's a GOOD thing from our standpoint as it makes it more likely the contract will remain viable long enough to pay off.

Per the specs on the S7, it might not be ABLE to undervolt - and almost definitely won't undervolt to the point a single 600ish Watt PS will run it.
UnderCLOCK might get there, can't hurt to try it.
 I don't see the point of that much underclock on it though, if you have to crank it down that far to be profitable, your electric rate is so high you really shouldn't waste power on mining.


 Unlike previous Bitmain miners, they are NOT running the S7 at the max voltage rating of the BM1385, they actually picked the MIDpoint of it's (so far) published voltage options.

 rare, perhaps. last a long time, NOT EVEN CLOSE.



 The S7 is arguably priced a bit high, but for the performance it offers the price is not "ridiculous".
 I was figuring it would be a 2.34 TH 550ish watt miner pre-release - at about 4 BTC.
 Instead, it's over twice the hash at about twice the power for right about twice the cost.

 No, the Bitmain power supply requires a 220V outlet, which most apartments do not have.

 If your apartment has an outlet for an electric dryer or an electric range, you COULD hook it up via that and it would work.

 If you use a standard ATX type power supply of 1200+ watts with enough PCI-E cables, a standard 15A 110V outlet WOULD handle that.



 Depends on your electric rate.

 Dunno where they got that answer from, but it's WAY on the low side.

 16 AWG in most usage is good for at least 8 and possibly as high as 10 amps.

 The national electric code doesn't go that low, but if you take their rating for 14 AWG (a VERY VERY conservitive 15 amps) and pro-rata for the relative circular mil area of a 14AWG to a 16AWG you get a much more accurate while still conservative figure.



 BAD timing.
 8-O

 I found a few options on Newegg when I did a power search yesterday - 3 platinum with enough connectors, but 2 of them were under 1100 watt (and flat out don't have enough +12 rail capasity), and a few Golds - the other was the Seasonic 1200watt platinum unit IIRC.
 The one concern I would have on a few of these is "split connectors" on one cable if the cable isn't 16AWG or better.

 Quite a few others like the EVGA 1300G2 and Seasonic X1250 that WOULD work if you're willing to risk the "use 2 connectors per hash board" option, or do some custom cable work to spread the load out, especially if you can use the EPS12V output and rewire the other end with a 6 pin connector instead of an 8 (perhaps use the left-over +12 and ground lines to wire a controller-specific connector to?).


 

 I'm kinda leaning towards server PS for these though, $200 or so of Bladecenter H 2880 watt+breakout+cables will power 2 of these comfortably, and I'm easily capable of wiring up a 220 outlet to power it. I just want to find a cheaper source for NEMA 6 series outlets/plugs/cables than what I've seen so far.

 They don't state that PICMAC v3 uses S5s. they talk about an "ideal S5" as the basis for the electric price thing.

 I would BET they have replaced all of their own S5s, or virtually all of them, with S7 or "S7+ type" units.


 S5's should still be profitable up to the halfing, at common electric rates.
 They might be profitable for a short while after the halfing, if you have CHEAP electric and the diff don't rise a lot more than 3% or so on average 'till then.
 They might be profitable for a LONG while past that if you have one that can be undervolted successfully and invest in the lower-voltage power supplies needed.

You keep SAYING that "only now are new 28nm chips being sold".
This is NOT accurate as stated, as I've already pointed out.

 I think what you mean to say is "only now are NEXT GEN 28nm chips being sold" or some such, which has a TOTALLY DIFFERENT meaning from what you are actualy STATING.


 Personally, I think your entire argument is based on false assumptions. SHA256 ASIC has seen "gaps" in new tech introduction before, the current one is more about the low bitcoin price forcing out some of the marginal performers than about the cost making new tech "not effective".

 The other factor clouding things is that many of the remaining SHA256 ASIC have gone out of retail, making it harder to verify when they had "new tech" in production - KnC and Bitfury in particular seem to have introduced and started production on "new tech" this year, but non-BIG-commercial-miners don't see their product in the wild so they end up under the radar and not registering as having appeared.


 Bitmain has been producing their BM1385 for a while now, we just don't know EXACTLY how long as the initial production went into replacing THEIR OWN miners.



 Windows Vista wasn't an epic fail, though it was at least arguably a fail.
 It says a lot that Vista support was ended by M$ about the same time (same date, or a few months LATER than) they ended XP support.

 Windows 8.x, Windows ME, and ESPECIALLY MS-DOS 4.0 were the EPIC fails of M$ operating systems.

 Says a lot about MS-DOS 4.0 that is led to M$ having it's first WIDE BETA of an OS (MS-DOS 5.0) - and they didn't do that again 'till the current Windows 10 beta which speaks to how epic the Windows 8.x fiasco has been.

the .8 (not .08) satoshi/sec seems to be skimmed "off the top" of the payout and becomes the "profit", THEN the balance of the payout is applied to "payback of the principal".

 Ignore the 0.098 electric cost thing for a couple months, that was a misreading of the contract terms and should have no effect for a while. My best estimate is that a S5 will be profitable at 0.098 electric right up to the halfing - they might still be profitable AFTER the halfing at my "non-summer" 0.067 incrimental electric rate, if the halfing wasn't due to happen soon after the time my rates kick up for the summer (though I hope to be ELSEWHERE with cheap electric by then).

 I figure the V3 contracts won't hit "no more payout" status as of the halfing, if not then VERY VERY shortly thereafter, unless bitcoin prices kick up quite a bit before that or difficulty flattens back out to well under 2%/round on average (yeah, SURE it will..... NOT!).


 Based on what I'm seeing out of my "trial" contract, looks like payback will be ballpark 100ish days, possibly as high as 120 with the RECENT difficulty rate of increase.

 Not when it first appears, but it does get there - and is often STILL the state of the art when it DOES achieve mass production for 1-2 years in semiconductor fab.
 I don't count "experimental in the lab only" as "state of the art", BTW.



 The BM1384 (among other examples) wasn't new in late 2014 when it was first released?
 You seem to have a very narrow definition of "new".
 Perhaps you meant "second generation on the 28nm process node" instead?



 It appears a FEW companies disagree with your belief, and you just shot your OWN "belief" statement down with the "profitable" statement given the facts.

 I'll remind you that at least one company claims to have had 16nm chips IN PRODUCTION for a while now (KnC), though I concede they aren't selling to end users.

 On the other hand, another (Innosilicon) has already announced tape-out of 14nm implying "in actual production" soon (December timeframe given Lktec's announced miner etc. etc.) and given Innosilicon's track record I'm CERTAIN they will be making miners shortly after the chips hit mass production.

 15 amp 110 is the DEFAULT, that's good for up to a 1600 watt PS based on what companies are actually making.

 Also, the "1210 watt" figure Bitmain quotes is AT THE WALL with a 93% efficiency PS.
 The actual draw FROM the PS should be about 1125 watts - the EVGA commonly used should have about 15% in reserve, the X1250s I use would have a bit over 10%.




 I'm presuming that's a reference to cheap hydropower
 Perhaps someone has done so but just doesn't choose to advertise?
 IIRC some of the Chinese farm locations I've seen mentioned are in "near the Himalayas" areas, those would tend to stay pretty cool most of the time.



 You got S5s for around $250?
 MUST be nice to have had the money to take advantage of the price war back then.

 (yeah, I know BTC had a small roller-coaster ride this year though mostly down).

 Hint - BTC pricing changed since then, 2 weeks ago you couldn't find ANY .5W/GH machine much under about 1.5BTC per TH unless you got VERY lucky and a lot of them were running very close to 2 BTC/TH even USED.
 Also, Spondoolies got out of the market entirely so Bitmain lost pretty much any competition on new units (unless you wanted low-efficiency stuff like Avalon 4.x).

 You need to look more at the capsity of the 12V line than the raw wattage.
 The PS needs at LEAST 30A for the hash boards alone ON ONE RAIL, preferably 35A for any safety margin, and AT LEAST 3 PCI-E connectors, not "split" unless 16AWG wiring is used.
 Then add 5A if one PS is running both a hash board AND the controller board AND one more PCI-E connector (Fans will eat at least 4A alone).
 
 The design of the hash boards makes it appear you MIGHT be able to get away with 2 per hash board, but DEFINITELY NOT SPLIT PCI-E if so unless 16AWG or better is used.


 The S5 had that SAME warning about turn on order, just need to be sure the controller is on the last PS you turn on if you use multiple PS.

 With only 2 PCI-E connectors I doubt that Corsair will work at ALL.
 Probably a split-rail design with less than 30A on either rail.
 Additionally, I doubt the wiring is heavy enough.



 You want at least a Gold PS, not a Bronze. It's a noticeable efficiency loss that WILL cost you significant money.
 The 40A rail is good.
 The connectors look like a split pair, but I couldn't get the picture with the "better" view of the cabling to load. IF they are NOT split, it should work.

 No clue what "market price" you're talking about offhand, but I suspect it would relate to S7 announcement + bitcoin price drop earlier this month + difficulty increase?

 Agree entirely with the first part - Bitcoin ASIC initial tech was a few generations behind the "state of the art" when the first ASICs started being designed.
 The gap has NOT entirely closed though - ASIC tech is still behind the state of the art, just not as MUCH behind it now.


 Several designs from late-2014/early 2015 were 28 nm, BM1384 being probably the best known "home miner" example.
 I'm pretty sure I remember the KnC Neptune/Titan and I believe the Spondoolies "Rockerbox" based machines like the SP20E and SP35 were 28nm as well.
 Bitfury also announced they were shipping 28nm around that timeframe, but since they went "no end user sales, just BIG corporate sales" it's hard to verify details on them.

 I do think that the drop in BTC price did kill off some of the weaker/less competant manufacture folks. Too bad it didn't kill off KnC. 8-(


 I don't think they'll bother trying, they probably have tapped 28nm out pretty close to it's limit.


 Then explain why KnC has announced it's already deploying 16nm (Solar).
 Explain why both Bitmain and Bitfury have announced they're working on 14/16nm "next gen" designs, and I believe all 3 have announced plans to deploy "full custom" designs on one of those tech nodes (Bitmain definitely has, Bitfure and KnC's claims about their NEXT gen imply it).
 SOMEBODY thinks it's worth working towards the current state-of-the-art, even where they won't deploy it for likely another year or more.



 BTW - my CPU and GPU on my primary machine happen to use the same identical technology. AMD A10 based custom build.

 There weren't as many Bitcoin ASIC makers "back then" as you seem to think - don't forget to ignore the scams.
 I think it's fair to count the folks that actually did the work to deliver, even if they were like BFL or KnC and ended up ripping folks off through VERY VERY late deliveries and/or failing to meet performace spec announcements.

 Bitfury and KnC are more likely to RoI with their own 'cause they don't have "distribution markup", than because the designs are not cost effective. That's the one BIG disadvantage home miners face, we pay a LOT more for the machines than the manufacture does for the parts and labor to build them.

The age of industrial mining goes back years. Nothing new there.

 8-(

 Seems to depend on when you bought your S5 - I got 2 coupons for buying out of the first "batch 7" (used) group.

 Not sure if I'm going to use both, but definitely plan to use one of them when I get the coin together.

 The S5 might have "officially" limited at 35C, but it could run hotter - just had to downclock it some.
 Mine have seen brief periods pushing 40c ambient.
 I'm sure the S7 will run at >40, just that's the max temp the "specified" rate is more-or-less guarenteed to be achieveable at.



 It varies, the "Time of Day" rate here (which I presume is the sort of tariff you're talking about) DOES in fact save money for anything that's on 24/7. +40% for 65 hours vs -50% for 103 hours, which is actually inferior to the "ToD" rate modifications from the last 2 places I lived.



 Unfortunately, by recent Bitmain pricing standards, it's not overpriced. It's actually a hair LESS than I expected for the TH and power draw.